.btn {
  border: none;
  border-radius: 5px;
  color: #fff;
  position: relative;
  padding: 10px 20px;
}
.after {
  width: 100%;
  height: 100%;
  position: absolute;
  border-radius: 5px;
  left: 0;
  top: 0;
}
 .btn:active .after {
  background-color: rgba(0, 0, 0, 0.11);
}
